I also had gastric bypass 14 years ago. Diane has given good advise in her post. Stay away from carbonated drinks until you are really well healed, they will cause great pain. (ask how I know).
I found there is a learning curve involved with eating and it takes time to learn what causes difficulties. I still cannot eat hamburger, it just doesn't digest, ice cream and a glass of milk, any food with high fructose corn syrup will cause serious gastric distress, I know of other people who can't drink coffee or eat chicken. I think almost everyone has a food or drink that just doesn't work.
As far as what to cook for the family, I don't prepare separate meals, the family and I eat the same foods, I just eat much smaller portions.
Think of this as another new adventure. Best wishes,